To provide a method for easily calculating a parameter indicating the status of an object to be monitored, a method for monitoring the status of the object by using a parameter, a parameter calculating device, a status monitoring device, a status monitoring system, a computer program and a recording medium.

The vibration of a rolling bearing having m pieces of rolling elements is observed, and when any abnormality is caused in one rolling element as an initial failure, vibration data including a large signal for every m pieces are obtained. The data of the vibration of the object being a periodic moving body such as a rolling bearing are measured by a sensor 31, and the measured data are displayed at a data display device 51, and a parameter I1 being the primary auto-correlation coefficient of a signal column is calculated by a simple formula from the number of signals, N, magnification s of the absolute value of the large signal to the absolute value of a signal other than the large signal and the number of signals, m included in a signal column per one large signal, and when the value of the parameter I1 is less than a predetermined value, it is determined that any abnormality is caused in the object to be monitored.